一种基于不变特征的视频拼接方法

视频拼接是空中监视的一个关键部分,它有助于人们从全局的角度理解监控场景.视频拼接包括图像的配准和融合两部分.提出了一种基于不变特征的视频拼接方法,它通过相邻两帧的拼接来实现全景图的拼接.该算法配准部分首先采用梯度方向直方图确定相邻两帧的旋转角度;其次检测两幅图像的角点,特征描述采用SIFT,并结合旋转角度对特征点进行粗匹配;然后对粗匹配的结果采用RANSAc算法剔除错误匹配点.融合部分采用灰度加权的方法.实验结果表明,该算法能够有效地进行视频拼接,甚至存在运动目标的干扰下也能够完成拼接,具有鲁棒性好和速度较快的特点.     

大攻角飞行空空导弹鲁棒自动驾驶仪设计

当前,导弹自动驾驶仪多采用经典设计方法。是在导弹气动参数变化不大、通道间的耦合较小的情况下设计的。为了满足导弹高机动性能要求,常采用大攻角飞行;然而导弹大攻角飞行时,将会出现空气动力学系数不确定性、非线性和通道间的严重耦合问题,这就要求所设计的自动驾驶仪具有较好的鲁棒性。就导弹在大攻角飞行状态下、通道间解耦的基础上,针对空气动力学系数不确定性,用μ方法对俯仰通道驾驶仪进行了设计,仿真表明该方法具有较好的鲁棒性能。     

从简单句的切分看俄语词序

俄语词序有很大的自由度,但要受词汇、语法、交际目的和修辞色彩的限制,不能任意安排。本文拟从简单句的结构切分和实义切分着手分析,来了解俄语词序的一般规律及其功能。     

基于DJI分步实现的联机空间距离查询处理

综合考虑了查询处理时的计算费用和存储费用,提出了距离连接索引(Distance associatedJoinIn dices,DJI)的分步实现方法,以高效地支持联机空间距离查询。该方法采用分阶段计算DJI的策略,根据用户的查询条件动态地计算DJI的一部分以支持查询。实验研究证明,与传统方法相比,DJI的分步实现方法在性能上具有较大优势。     

车辆 GPS 定位的一般性问题研究

为了适应现时特种车辆管理系统对车辆GPS定位的精度的需要 ,并考虑到未来的发展趋势 ,对差分GPS方案进行了介绍。针对上述方案的不可靠性问题提出了一种车辆路径匹配定位方法 ,并通过实验证明了这种方法不仅可以提高定位精度 ,同时还有效地避免了车辆在电子地图上显示混乱的问题。     

流化H.264编码的数据并行方法

流模型是一种源于媒体处理的新型并行计算模型.然而H.264编码作为媒体处理领域中的重要应用,在与流模型适配时,却出现重要障碍,主要是由于相关性问题极大地限制了流化过程中数据级并行的开发.针对这个问题,首先根据编码算法分析了编码过程中遇到的相关性问题,然后为各主要编码模块分别提出解除相关性限制的数据并行编码方法.采用这些...     

某型装甲车辆侧减速器被动齿轮齿部硬度分布规律研究

介绍了某型履带式装甲车辆侧减速器被动齿轮的功用、材料、常见故障与维修,详细叙述了被动齿轮的试件准备和硬度测量过程,对硬度测量结果进行了数据分析,并讨论了测量误差的产生原因.这些测量结果为被动齿轮的疲劳可靠性分析提供了基础数据.     

Retailer's rationale to refuse consumer returns in supply chains

While accepting consumer returns has long been proposed as a solution to resolve the consumer valuation uncertainty problem, there are still a sizable portion of retailers who insist on a “no return” policy. In this article, we offer an economic rationale for these seemingly unreasonable strategies in a supply chain context. We demonstrate when and why the retailer may benefit from refusing consumer returns, even though offering consumer returns allows the supply chain to implement the expostmarket segmentation. Granting the retailer the right to refuse consumer returns may sometimes improve supply chain efficiency: it eliminates the manufacturer's attempt to induce inefficient consumer returns and bring the equilibrium back to that in the vertically integrated benchmark. We also find that the refund and the retail price can move in the opposite directions when product reliability varies, and consumer returns have a nontrivial impact on the quality choice. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 686–701, 2015     

Impact of reseller's and sales agent's forecasting accuracy in a multilayer supply chain

We consider a three‐layer supply chain with a manufacturer, a reseller, and a sales agent. The demand is stochastically determined by the random market condition and the sales agent's private effort level. Although the manufacturer is uninformed about the market condition, the reseller and the sales agent conduct demand forecasting and generate private demand signals. Under this framework with two levels of adverse selection intertwined with moral hazard, we study the impact of the reseller's and the sales agent's forecasting accuracy on the profitability of each member. We show that the manufacturer's profitability is convex on the reseller's forecasting accuracy. From the manufacturer's perspective, typically improving the reseller's accuracy is detrimental when the accuracy is low but is beneficial when it is high. We identify the concrete interrelation among the manufacturer‐optimal reseller's accuracy, the volatility of the market condition, and the sales agent's accuracy. Finally, the manufacturer's interest may be aligned with the reseller's when only the reseller can choose her accuracy; this alignment is never possible when both downstream players have the discretion to choose their accuracy. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 207–222, 2014     

Return policy: Hassle‐free or your money‐back guarantee?

This article compares the profitability of two pervasively adopted return policies—money‐back guarantee and hassle‐free policies. In our model, a seller sells to consumers with heterogeneous valuations and hassle costs. Products are subject to quality risk, and product misfit can only be observed post‐purchase. While the hassle‐free policy is cost advantageous from the seller's viewpoint, a money‐back guarantee allows the seller to fine‐tune the consumer hassle on returning the product. Thus, when the two return policies lead to the same consumer behaviors, the hassle‐free policy dominates. Conversely, a money‐back guarantee can be more profitable even if on average, high‐valuation consumers experience a lower hassle cost than the low‐valuation ones. The optimal hassle cost can be higher when product quality gets improved; thus, it is not necessarily a perfect proxy or signal of the seller's quality. We further allow the seller to adopt a mixture of these policies, and identify the concrete operating regimes within which these return policies are optimal among more flexible policies. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 403–417, 2014